Whistler is a year round outdoor destination, skiing and snowboarding in the winter, mountain biking in the summer, you can go bungee jumping, they have ziplines, best hiking trails ever, etc.
The Vancouver 2010 olympics had a variety of the events held at whistler.
I've been biking in some crazy places, croatia, south america, etc. All I can say is that when I return home and hit up the bike park at whistler, I remember why this region is mountain biking meca.
Only the lower portion of the hill is open at this point (this portion opened over a month earlier than usual due to the warmer than average conditions), but a myriad of technical and flowy trails open ranging from green runs to double blacks.
Opened my day up on a nice flowy blue run, and then took it to A-Line:
https://www.youtube.com/watch?v=LlXYyqSKH64
Whistler is in a weird kind of place right now, the blackcomb side of the mountain is open to skiers and boarders and whistler itself is open to mountain biking. So we hit up the bar afterwards and talking with people around us a bunch of them had just had a crazy day snowboarding the terrain park, while we had been shredding the bike park. It's a really odd thing, and probably one the only places in the world you could conceivably, ski, mountain bike, and hit the beach in the same day.